Read the docs
TI-2026-73994 Aliases CVE-2026-53612

Race condition in util-linux mount hook allows privilege escalation

Priority HIGH 66CWE-367Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

util-linux from 2.39 before 2.41.5 and from 2.42 before 2.42.2 is affected. The SUID mount utility's post-mount hook changes ownership and mode by path after checking the mount target, a time-of-check to time-of-use race (CWE-367). A local low-privileged user with a user or users fstab entry that uses an X-mount.mode, X-mount.owner or X-mount.group option can race a writable ancestor of the target to redirect that change to a root-owned path, potentially gaining root privileges.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00152 4th percentileScored 2026-11-07
Fix Fixed util-linux (util-linux): 2.41.5, 2.42.2Red Hat: 2 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
util-linuxutil-linux2.39 to before 2.41.5; 2.42 to before 2.42.22.41.5, 2.42.2Patch availableCNA
  • util-linux Vendorutil-linux Affected 2.39 to before 2.41.5; 2.42 to before 2.42.2 Fixed in 2.41.5, 2.42.2 Patch available CNA

Remediation

Update util-linux to 2.41.5 or 2.42.2. Red Hat fixes it in RHSA-2026:93461 for Red Hat Enterprise Linux AppStream, BaseOS and CodeReady Linux Builder (v. 10), and in RHSA-2026:95365 for Red Hat Cost Management On-Premise 1.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA util-linux (util-linux) Fixed in 2.41.5, 2.42.2

Red Hat 2 advisories

  • RHSA-2026:95365 Released 2026-11-04 · Red Hat rating Critical
    Red Hat Cost Management On-Premise container image update
    • Red Hat Cost Management On-Premise 1 registry.redhat.io/costmanagement/costmanagement-ui-rhel10
  • RHSA-2026:93461 Released 2026-11-02 · Red Hat rating Important
    util-linux security update
    • Red Hat Enterprise Linux AppStream (v. 10) libblkid-devel-2.40.2-18.el10_2.20, libmount-devel-2.40.2-18.el10_2.20, libuuid-devel-2.40.2-18.el10_2.20 +2
    • Red Hat Enterprise Linux BaseOS (v. 10) libblkid-2.40.2-18.el10_2.20, libfdisk-2.40.2-18.el10_2.20, libmount-2.40.2-18.el10_2.20 +4
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libfdisk-devel-2.40.2-18.el10_2.20, libsmartcols-devel-2.40.2-18.el10_2.20

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Cost Management On-Premise 1Fixed RHSA-2026:95365
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:93461
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:93461
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:93461
Not affected: 6 products
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-14 Threatist record created from CVE-2026-53612
  2. 2026-10-15 CISA SSVC decision points changed
  3. 2026-10-15 Priority changed: MEDIUM → HIGH
  4. 2026-10-30 Affected versions changed · Red Hat
  5. 2026-11-02 Fix available: RHSA-2026:93461 · Red Hat
  6. 2026-11-02 Fix available: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · Red Hat
  7. 2026-11-05 Fix available: Red Hat Cost Management On-Premise 1 · Red Hat
  8. 2026-11-06 Fix available: RHSA-2026:95365 · Red Hat

References

Other 7

  • TI-2026-53553 util-linux libmount Privilege Escalation via Failed Mount Helper CVSS 4.0HIGH 8.5
  • TI-2026-74163 Integer overflow in util-linux libblkid DOS extended partition parsing CVSS 3.1HIGH 8.0
  • TI-2026-73996 util-linux LIBMOUNT_FORCE_MOUNT2 allows nosuid and noexec bypass CVSS 3.1HIGH 7.0
  • TI-2026-73995 Race condition in util-linux mount lets local users gain root CVSS 3.1HIGH 7.0
  • TI-2025-12886 Util-linux: util-linux: heap buffer overread in setpwnam() when processing 256-byte usernames CVSS 3.1MEDIUM 6.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences